1. Field of the Invention
The present invention relates to drug administration, and more particularly, pertains to a process for determining drug taper schedules by an algorithm which can be implemented by a computer.
2. Description of the Prior Art
Use of drug tapers is important in many fields. Experience shows routine use in detoxifying patients admitted for chemical dependency, but it also occurs when withdrawing patients from different drugs which they have used for long periods of time. In addition, when patients have been on drugs where rebound effects may be dangerous, drug tapering is necessary.
Previously, drug tapers have been calculated by hand, and they have been typically a "linear" taper. For example, a "10%" taper from 500 mg would go 500, 450, 400, 350, 300, 250, 200, 150, 100, 50. An exponential taper of this program would be, e.g., 500, 450, 405, 365, 329, 296, 266, 239, etc. The other approach that has been used has been to recalculate the drug taper on an almost daily basis, by the "seat of the pants". In other words, the physician may drop the patient from 500 mg to 450 mg one day, observe him the next, and then based on clinical experience, guess what the next drop should be, then continue this process on a daily basis. If a patient encountered difficulties using the "linear taper", such as showing signs of withdrawal or intoxication, then the "seat-of-the-pants" approach was the only approach that could be used.
The literature in the field generally agrees upon the need for a "gradual" taper, but the specifics of such a drug taper are generally not published. The approach usually taken involves either a slow linear taper where a fixed percentage of the starting dose is taken away over every period of time, a stepwise taper where patients are dropped by a fixed percentage and then held at the next step for a period of time before the next reduction, or a combination taper where the patient has an initial large drop followed by a linear taper.
When drug detoxification has been studied, it has been found that the actual requirements for drugs are not easily determined by biochemical parameters. That is, the amount of drug a patient needs is not necessarily reflected by, for example, serum levels. Rather, it appears that a patient's requirement for drugs during detoxification is a complex determination, effected by many physical, psychological, and social factors.
The traditional linear taper chooses a certain percentage of the initial dose, and then reduces the dose by the same absolute amount over each time interval. This is unsatisfactory, as it leads to ever increasing percentage decrements. This same problem occurs in both the step-wise taper and also over the major portion of the combination taper. In addition, the linear taper is inconsistent.
Consider a patient being detoxified from a total daily dose of 500 mg using a 10% linear taper. This patient will have his dose reduced by 50 mg every twenty-four hours. When this patient reaches a level of 100 mg, he will then be reduced to 50 mg, then none over the next two days. However, if this same patient were being detoxified from a total daily dose of 200 mg using a 10% taper (i.e., a reduction of 20 mg every twenty-four hours), the reduction from 100 mg to none would take two and one-half times as long (FIG. 2).
Clinically, experience has shown that linear tapers have not been appropriate for patients. The Mayo Clinic's experience has shown that linear tapers do not work in the patients whom they see. Rather, one finds that patients do best when they have larger decrements earlier in the drug taper schedule, and smaller decrements later.
The present invention overcomes the disadvantages of the prior art by providing drug tapers to give the patient the minimum amount of drug required at any given time and to prevent the emergence of any type of abstinence syndrome or rebound effect.